Forming and treating electrical carbons



(No Model.)-

- J. H. GUEST.

FORMING AND TREATING BLBGTRIGAL GARBONS. No. 256,213. Patented Apr. 11,182.

NFTE STATES PATENT. Frtce.

JOHN H. GUEST, OF BROOKLYN, NEW YORK.

FORMING AND TREATING ELECTRICAL CAEBONS.

SPECIFICATION forming part of Letters Patent No.v 256,213,dated April 11, 1882.

Application filed September 7, 1881. (No modeh) v cial form of such loop and in a mode of treating the loops so as to perfect the same and increase their hardness and permanency, and

also to enlarge the attaching ends or heels of the loop 'for better attachment with the circuit-wires,as hereinafter fully set forth.

Carbon loops, as is well known, have been treated with an electro-deposit of carbon to harden and strengthen the same, which has been done both before and after the loop was attached to its circuit-wires and inclosed in its enveloping exhaustedglobe, and the deposit of carbon has in some cases been uniform throughout the loop, while in other cases it has been increased or enlarged at the attaching ends. In my system I employ these expedients, but in a somewhat different manner, whereby improved results are attained, as hereinafter set forth.

In the annexed drawings, Figure 1 repre sents my improved carbon loop just after the same has been carbonized, and Fig. 2 shows the same after treatment to perfect the same and enlarge its ends by the electro-deposit of hard carbon. Fig. 3 represents the third stage in the manufacture of the loop, with the circuit-wires applied thereto, and Fig. 4 represents the finished stage with the attachment of the circuit-wires completed. Fig. 5 presents a sectional elevation of an apparatus employed in treating the carbon loops.

I prefer to form the carbon loops in the shape shown in Fig. 1, as this is advantageous and constitutes one feature of my invention. This loop may be described as of oval or circular form,bent in upon itself at the middle, forming a secondaryor minor loop within the outer vor larger one, the shape being hence that of two concentric arches joined at their bases. ThlS shape, as may be observed, has the advantage of including a long filament in acompact space, and, moreover, is strong and substantial, for it will be observed that both parts of-the loop tend to re-enforce or balance each other. Thus the tendency of the inner archis to fall down and spread the outer arch, while thelatter tends itself to fall in or close together and to counteract the tendency of'the inner arch, thus rendering the whole form strong and stable. This loop may be formed from any suitable carbonaceous material, fibrous or otherwise; butI prefer to form it from a slender strip or filament of bamboo, which strip is at first reduced to the proper size and shape by draw-plates or other reducing-tools previous to carbonizing. The filament thusreduced is next bent into the described shape, as shown in Fig. 1, and is placed between two closely-fitting iron plates, which are thence placed in a furnace or crucible and subjected to a high heat to thoroughly carbonize the filament, after which'th'e plates are withdrawn and cooled and the carbonized loop removed,

when it will appear as shown in Fig. 1. One

of the aforesaid iron plates is studded with a number of curved projections or circular pins so disposed as to correspond to the form of the loop, so that the bamboo strip is easily curved into the proper shape by simply bending it around the projections previous to clamping the two plates together. I

The bamboo filament from which the loop is madeis necessarily of uniform size throughout, whereas it is desirable to have the ends of the finished loop where the circuit-wires attach thicker than the rest. It will be also understood that although the bamboo strip from which the loop is formed be of uniform thickness, yet after this strip has been carbonized it will frequently show manyirregularities, being thin at some parts and thick at others, whereas it is quite important that the partof theloop which is to become incandescent should be as uniform as possible throughout. To effect these results it has been usual to heat the carbonized filament to incandescence in an atmosphere containing some carbon compound, either by the passage of an electric current, or otherwise, which produces a depositof carbon on the filament, and an increased deposit has been produced on the heels or ends of the filaments to enlarge the same. a

In Fig. 5 is shown a sectional elevation of my apparatus for performing these operations, in which (t represents a suitable base,from the center of which rises a form of Argand gasbnrner, b c. This burner consists of an outer tube or cylinder, b, into the bottom of which hydrocarbon gas may be admitted through the pipe and cock shown,and an inner cylinder or cup, 0, which depends into the former and is closed at its bottom but open at the top. Space is left between the two tubes, as shown, through which the gas may freely rise, and the top edges of the two tubes terminate nearly on a level and closely approach, so as to leave a narrow annular space between them to allow the escape of a narrow annularjetof gas, similar to the jet of an Argand burner, with the difference, however, that no air is admitted into the middle of the flame. The inner cup is preferably corrugated on its sides, and is capable of being easily lifted out of the tube 0, and its mouth is preferably flared to rest on a few short projections in the mouth of the tube 11, so as to be supported in central position in the gas-tube 1), yet leave an annnlarjet-space between the edges thereof, as will be understood.

From the base on each side of the gas-burner arise two tubular pillars, d d, into which fit two adjustable standa1ds,ee, which are joined in parallel rigid position byacross-bar,f, which is curved at its middle to pass around the burner b, so that the standards are thus held firmly together and may be adjusted up or down as one part in the pillars d d, and held at any desired position by the clampscrews g g. -Now, from the top of the standards 0 e tweezers or forceps h h project toward each other, and the tips of their jaws approach each other over the gas-burner and over the mouth of the cup 0, as shown.

In preparing to treat a carbon loop the standards 0 eand their attachments are raised or removed from the pillars d d, and the ends of the freshly carbonized loop as it appears in Fig. 1 are clamped in the respective forceps h h {,,and the standards, 810., are then adjusted in position, so that the loop hangs into the cup 0, as shown in Fig. 5. Now, the pillarsd d,

standards 6 e, and the forceps h h are of course made of metal or some conducting material,and they are respectivelyinsulated from each other, and the negative wire from a dynamo-machine or other source of electricity is connected with one of the pillars and the positive wire with the other pillar, so that if the circuit be closed the loop will form part of the circuit, and may be raised to incandescence by the passage of the current. A circuit-closing device should be used which will admit of turning the current on gradually, so as to raise the loop to any desired degree of incandescence, or to gradually increase its incandescence, as will be understood. Now,when the carbon loop is clamped and adjusted into the position as already described and shown in Fig. 5, but before the circuit is closed on the same, the gas is turned on in the burner 11 and ignited at the edge of the same, where it will form in a cone of flame above the cup 0, as illustrated. The heat of the flame being rapidly communicated to the burner b and cup 0, the air in thelatter will be rarefied, and will gradually diffuse with the gas from the interior of the flame, which gas will soon fill the cup 0 and displace the air, so as to form a hydrocarbon atmosphere around the carbon loop. In most cases, however, I prefer to increase the richness of this atmosphere by a small quantity of liquid hydrocarbon, preferably kerosene, either dropped into the bottom of the cup 0 or smeared by a brush on its sides, which liquid will soon vaporize and envelop the carbon loop with a rich carbonaceous atmosphere. When the atmosphere is thus formed around the loop,which will occur in a short time after the gas is lighted, the circuit is closed on the loop gradually, or rather'with gradually-in- I creasing strength of current. It is to be here noted, however, that according to my sys-' tem the current is not sent at first through the entire loop, but in a short circuit only through the ends or heels a n by means of a platinum wire, i, which rests lightly as a conductin'g bridge from heel to heel, as shown in Fig. 5, which wire is attached to an adjustable arm, m, having both a vertical and swinging adjustment on the standard a, in the manner illustrated, and preferably insulated from the standard. Hence when the circuit is now closed the heels of the carbon loop will be rendered incandescent, and the hydrocarbon atmospherearound them will become decomposed, and a deposit of fine hard carbon possessing a metallic quality and appearance will be formed on the heels, and this action is allowed to continue till the heels become considerably enlarged and strengthened by a thick layer of the deposit, as seen in Fig. 5. When thus sufficiently enlarged the circuit is broken and the wirei removed from the loop. The current is now turned on gradually, so as to pass through the entire loop, raising the slender parts or loop proper to incandescence. The thinner portions of the luminous loop will now be seen to possess a greater degree of incandescence than the thicker parts, and the deposit will form on the parts in proportion to their degree of incandescence, so that the thinner parts will become rapidly built up so as to by this simple and efficient system. After the treatment of the loop is finished, as in Fig. 2,

it is next attached in any suitable mannenas shown in Figs.-3 and 4, to the circuit-wires, which may be either platinum or copper.

I prefer to make the circuit-wires where they attach to the loop of copper, and to connect these copper wires at a little distance from the loop with platinum wires; but, if desired, platinum wires alone may be used.

Forthe purpose of electric lamps a loop form of the carbon is of course preferable; but my system of treatment hereinset forth is not of course confined to looped forms, but is equally adapted to straight or other forms of carbon filaments.

In lieu of the gas-burner shown for providing the carbon atmosphere, an oil-burner of similar form may be used; but it is not so desirable.

What I claim is- 1. An apparatus for treating ele'ctrical carbons, consisting of a burner adapted to emit a hollow flame, and means for holding a carbon within the hollow or the gases of the flame, and means for passing an electric current through said carbon or rendering it incandescent in the gases of said flame, substantially as herein set forth.

herein shown and described.

3. An apparatus for treating electrical carbons or carbon loops, consisting of a burner adapted to emit a hollow carbonaceous flame, in combination with adjustable forceps mutually insulated and adapted to respectively seize each end of the carbon and hold it in the hollow or gases of the flame, and means for including said forceps and the carbon held thereby in an electrical circuit, substantially as herein set forth.

JOHN H. GUEST.

Witnesses:

CHAS. M. HIGGINS, J NO. E. GAVIN. 

